1. Field of the Invention
The present invention relates to a variable comparison voltage generation apparatus for a semiconductor memory element. More particularly, it relates to a variable comparison voltage generation apparatus for a semiconductor memory element which maintains information safely although the number of times a ferroelectric substance memory element is usae becomes increased, and thereby accurately discriminates the data value in the memory element.
2. Description of the Prior Art
Generally, a semiconductor memory element memorizes information as two states according to an electric charge quantity therein. A comparison voltage amplifier is required for discriminating between the two-states of information and transmitting it to the outside. Accordingly, a comparison voltage is needed for the comparison voltage amplifier.
However, a memory element with a ferroelectric substance has a lower electric charge quantity, as its amount of usage is increased.
If the electric charge quantity decreases, a voltage value applied to an external voltage amplifier also decreases. Accordingly, it is difficult to accurately discriminate between voltages(information) stored in the memory element, so the memory element is not reliable.
In a conventional comparison voltage generation apparatus having a fixed comparison voltage, if a ferroelectric substance memory element is used in memory device, electric charge quantity decreases because the number of times the memory element is used, increases. Therefore, the conventional comparison voltage generation apparatus cannot accurately discriminate between the two voltages stored in the memory element, thereby incorrectly transmitting the stored information to an external part.